The present invention relates to a shutter and a disk cartridge having the shutter, and particularly to a shutter supported by a case body containing a recording medium in such a manner as to be slidable for opening/closing an opening formed in the case body, and a disk cartridge having the shutter.
A known disk cartridge has a shutter supported by a case body in such a manner as to be slidable for opening/closing an opening formed in the case body. In this disk cartridge, when information is not recorded or reproduced in or from a disk-like recording medium, the shutter closes the opening for preventing permeation of dust in the case body.
Specific markings for indicating a recording allowable time to the disk-like recording medium, the kind of the disk cartridge, and the like are often provided on such a shutter.
For example, in a related art disk cartridge of this type, as shown in FIG. 4, a shutter xe2x80x9caxe2x80x9d has a base member xe2x80x9cbxe2x80x9d and a covering layer xe2x80x9ccxe2x80x9d for covering the base member xe2x80x9cbxe2x80x9d, and a printing layer xe2x80x9cdxe2x80x9d patterned to correspond to specific markings is provided on the surface of the covering layer xe2x80x9ccxe2x80x9d with ink of a ultraviolet hardening type or a solvent type.
The related art shutter xe2x80x9caxe2x80x9d, however, has a problem that since an expensive printing plate is used for forming the printing layer xe2x80x9cdxe2x80x9d, so that the equipment amortization must be expedited by mass-production of the shutters xe2x80x9caxe2x80x9d.
In recent years, shutters have been required to be produced on a multi-kind and small-quantity basis to keep up with the market needs; however, for the above-described related art shutters xe2x80x9caxe2x80x9d using the printing plate for forming markings, the kinds of markings cannot be easily altered, thereby failing to readily, flexibly keep up with the market needs.
To keep up with the market needs, there has been known a method of forming markings in a surface portion of a shutter by cutting away regions, corresponding to the markings, of the surface portion of the shutter to a depth extending to part of a base member; however, in this case, since there is no difference in hue between the marked portions to be cut away and the remaining portion not to be cut away, the visibility of the markings is degraded.
An object of the present invention is to provide a shutter capable of reducing the cost required for forming markings and improving the workability in formation of the markings, and enhancing the visibility of the markings, and to provide a disk cartridge having the shutter.
To achieve the above object, according to a first aspect of the present invention, there is provided a shutter supported by a case body containing a recording medium in such a manner as to be slidable for opening/closing an opening formed in the case body. The shutter includes at least two layers composed of a base layer and at least one covering layer formed to cover the base layer, wherein a difference in hue between the uppermost layer of the at least two layers and the underlying layer thereof is in a range of two or more in hue cycle of the PCCS (Practical Color Co-ordinate System); and markings are formed in a surface portion of the shutter by cutting away regions, corresponding to the markings, of the surface portion of the shutter to a depth extending to the bottom of the uppermost layer or to part of the underlying layer through the uppermost layer.
With this configuration, it is possible to easily form markings without the need of using any printing plate and hence to reduce the cost required for forming the markings and improve the workability in formation of the markings, and also to easily alternate the kinds of markings and hence to readily, flexibly keep up with the market demands.
Further, it is possible to form markings with good visibility.
In the above shutter, preferably, a plurality of covering layer are used as the at least one covering layer. With this configuration, it is possible to freely set a difference in hue by suitably changing pigment components contained in the covering layers, and hence to improve the degree of freedom in design, and also it is possible to protect the base layer because the cutting depth scarcely reaches the base layer.
According to a second aspect of the present invention, there is provided a disk cartridge including: a shutter supported by a case body containing a recording medium in such a manner as to be slidable for opening/closing an opening formed in the case body. The shutter includes at least two layers composed of a base layer and at least one covering layer formed to cover the base layer, wherein a difference in hue between the uppermost layer of the at least two layers and the underlying layer thereof is in a range of two or more in hue cycle of the PCCS (Practical Color Co-ordinate System); and markings are formed in a surface portion of the shutter by cutting away regions, corresponding to the markings, of the surface portion of the shutter to a depth extending to the bottom of the uppermost layer or to part of the underlying layer through the uppermost layer.
With this configuration, it is possible to easily form markings without the need of using a printing plate and hence to reduce the cost required for forming the markings and improve the workability in formation of the markings, and also to easily alternate the markings and hence to readily, flexibly keep up with the market demands.
Further, it is possible to form markings with good visibility.
In the above disk cartridge, preferably, a plurality of covering layer are used as the at least one covering layer. With this configuration, it is possible to freely set a difference in hue by suitably changing pigment components contained in the covering layers and hence to improve the degree of freedom in design, and also it is possible to protect the base layer because the cutting depth scarcely reaches the base layer.